atomic weight

noun

Definition of atomic weight

: the mass of one atom of an element specifically : the average mass of an atom of an element as it occurs in nature that is expressed in atomic mass units — see Chemical Elements Table

Examples of atomic weight in a Sentence

Recent Examples on the Web

How to Read the Table Many periodic tables include the atomic number (number of protons) and atomic weight (which depends on protons and neutrons). Bill Andrews, Discover Magazine, "Everything Worth Knowing About The Periodic Table," 26 June 2019 So Bormanis came up with his own fictional heavy element, dysonium (named in honor of physicist Freeman Dyson), something with an atomic weight in the 130-135 range—well above the transuranic elements in the period table. Jennifer Ouellette, Ars Technica, "The Orville blends science fiction and science fact into a winning mix," 29 Dec. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'atomic weight.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of atomic weight

1819, in the meaning defined above

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Last Updated

26 Sep 2019

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The first known use of atomic weight was in 1819

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More Definitions for atomic weight

atomic weight

noun

Medical Definition of atomic weight

: the mass of one atom of an element specifically : the average mass of an atom of an element as it occurs in nature that is expressed in atomic mass units — see Chemical Elements Table

More from Merriam-Webster on atomic weight

Britannica.com: Encyclopedia article about atomic weight

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